ELECTRON THEORY

An electron is a very small piece of matter and energy. Its symbol is e⁻. It was discovered by J.J.Thomson in 1897. The electron is a subatomic particle. It is believed to be an elementary particle because it cannot be broken down into anything smaller.
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An electron is a negatively charged subatomic particle. It can be either free (not attached to any atom), or bound to the nucleus of an atom. Electrons in atoms exist in spherical shells of various radii, representing energy levels. The larger the spherical shell, the higher the energy contained in the electron.